Code impulse signaling system.



J. G. ROBERTS.

CODE IMPULSE SIGNALING SYSTEM.

APPLlcATloN HLED JULY 12. 1913.

Patented Oct. 17, 1916.

'Affy J. G. ROBERTS.

CODE IMPULSE SIGNALING SYSTEM.

APPLICATmN F|LED1U1Y12,1913.

Patented Oct. 17, 1916.

3 SHEETS-SHEET 3.

I/V/'f/vesses: /m/en/o/f.' y dw.. Joh/7 G. Rober/s.

6MM by l.

JOHN G. ROBERTS, OF DOBBS FERRY, NEW YORK, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION' OF NEW YORK.

CODE IMPULSE SIGNALING SYSTEM.

Specification of Letters Patent.

Patented Oct. 17, 1916.

Application filed J'uly 12, 1913. Serial No. 778,749.

ful in telephone exchange systems, although not limited to such use.

In automatic and semi-automatic exchange systems it has been the practice tocontrol the switching operations by a sender or calling device adjustable to transmit for each character or numeral of a subscribers number, signaling' impulses varying in number from 1 to l0. In such systems the switching apparatus is caused to move in each instance a. distance corresponding to the number of impulses. It has also been the practice in so-called full automatic telephone systems to omit all ground connections at the subscribers station and to utilize for signaling a metallic circuit including the two line wires which subsequently form part.

of the telephonie circuit, the sigaling iinpulses being produced by momentary interruptions of the circuit following the initial closing of it when the subscriber lifts his telephone receiver to call. The present invention is particularly applicable to such `groundless metallic line systems, and as a method is distinguished from the method hitherto practised in that the impulses are produced by combinations or a code of different kinds of impulses.` Preferably two kinds of impulses are made use of, one a. full impulse produced by a full interruption of the circuit and the other a partial impulse produced by an interruption of the circuit with a resistance in shunt of the interrupting switch. lVith this method, the maximum number of impulses required for the characters or numerals of subscribers numbers are very much less than that required for systems heretofore used. By using two kinds of impulses and varying their order of succession, a code for twelve characters may be produced by a maximum of three and a minimum of two impulses for each character, thereby providing for `the ten numerals,0 to 9, and allowing two yadditional y characters, which for convenience may be designated Xvand Y.

The invention contemplates'not only a method of transmitting signals, but also a method and apparatus for receiving, trans lating and recording thev signal indications.

For a more completeunderstanding of the invention, referenceniay be had to the. following detailed description'- and claims in connection with the accompanying drawings wherein- Figure l is a diagrammatic representation of circuits and apparatus exemplifying and embodying the invention; Fig. 2 is an i elevation, partly in section, of a recording dev1ce; Fig. `3. is an end view in section on line 3-3 of Fig. 2 with a part cut away to 75 show `a detail of the construction; Fig. 4 is an end View in section on the line 4 4 of Fig. 2; Fig. 5 is a detail showing a sp1-ing motor device used inhthev recorder; Fig. 6

is a detail cross-sectional view on the line 6 6 of Fig. 2;'and-Fig. 7 is a tabulation or code of current waves or'impulses for signaling in accorda-nce with the invention.

The recording device, although not of itself the invention'herein claimed, should be 85 understood and'will be described first. Itl may be located at the central office of a telephone eXchange 'and'serves as a register of the signals sent from theI subscribers calling devices.' It comprises a series of electro- 90 magnets 2l, twelve 1n number, individually.

designated by the numerals. 0 toj9 and the letters X and Y and arranged marc formatlon; a serles of electromagnets 22, seven in v number, individually jdesignated22a to 22g 95y inclusive and arrangedin" circular 'formation; a spring motor dev-i'cef'23, anelectro-l magnet 24 for winding the springy of the mo-tor and seven sets' of stepping and releasing magnets 25 and 26, respectively, although 100 but two sets are shown. In such a recorder there are seven sections, although any number of sections may be employed according to the requirements of the system. Seven sections permit the recording of a number having seven numerals or combinationsof numerals and letters.

The various electromagnets mentioned are mounted upona frame which comprises a trunk 27, at the lower end of which is a base plate 28 and at the lupper end a plate 49.

and at its lower end a plate 36. Held be- -on the outside-of the bars,

tween plates 35 and 36, and arranged in semi-cylindrical formation, is a series of bars 37. These bars 37 are separated sufficiently to leave spaces between them for a series of pivoted levers 38. There are twelve of theselevers for each section of the re'- corder or eighty-four in all; they lie in arcs corresponding to the arc arrangement of the electromagnets 21. The levers are pivoted between the bars by means of wires 39 threaded through them and drawn tightly across the bars, there being one such wire for the twelve levers of each sction. Each lever is formed of thin spring metal bent in a U shape with one arm longer than the vother and sprung into the' space so as to bear with some pressure against theedges of the bars 37. The longer arm 42 extends beyond the inside surface of the bars 37 and is given about a 45O twist, the purpose of which as hereinafter described is to effect the restoring of the lever after being displaced. The shorter arm 43 of the lev,er is formed with a slight projection 44 to frictionally engage the edge of the adjacent bar. Two ears 45 and 46 project sidewise from the longer arm These serve as f' stops to limit the pivotal movement of the @5" ally attached to each rod 47 and arranged a pinion 48- and the plate 49.

lever.

Extending between the plates 35 and 36 are a series of rods 47, twelve in number, and

.tached to the pinion 'by means of a rivet 192 in order that the rod 47 may be given a turn-- ing movement by the pinion, while being capable of free endwise movement without displacing the pinion. Normally the rod 47 is retained in the position shown in Fig. 2 ,by a retracting spring 52, which isvone of the arms of a spider 53. The other arms of the spider serve a like function for the other rods 47. A series of seven pins 54 are radispirally so that in seven angular positions of the rod the seven pins 54 will be brought successively into operative position with respect to the seven levers 38 inline therewith i'n the several sections of the recorder. In any one of these seven positions there will be one of the pins 54 adjacent the outer end of a lever 38 of some section of the recorder, and upon the energization of the corresponding electromagnet 21, the rod 47 will be displaced endwise, bringing the pin into engagement with the lever, and rocking the `latter so that the outer end of it will point upwardly instead of downwardly as in the normal position shown in Fig. 2.

The twelve pinions 48 are engaged by a gear wheel; 55 positioned between plates 36 and 49, and adapted to be rotated on the stem 34 as a bearing. A driving pinion 56 for this gear wheel is keyed to a shaft 57 which has its bearings inl an extension piece 58 of the plate 36, the top plate 49 and the stem 32. There is also keyed to this shaft a disk 59 on the periphery of which, and insulated from it, is a contact ring 61 covering the periphery of the disk, except at a point 62 which is of insulating material. A contact brush 63 supported on an arm 64 of thev frame, but insulated therefrom, bears upon the Contact ring 61. Fastened to the-disk 59 is a stop pin 60. A pin 65 also secured to this-disk supports the outer end of a spiral spring 66. The inner end of the spiral spring is fastened to the hub 67 which carries a disk 68 and a pinion 69..y The hub 67,

disk 68 and pinion 69 are made of one piece preferably, and are adapted to turn freely 011 the shaft 57 as a bearing. On the outer surface of the disk 68 is a contact ring 71 on which a contact'brush 72 bears. This contact brush is fastened to the arm 64 of the frame and insulated therefrom in the same manner as the contact brush 63. The contact ring 71 carries a brush 73 which normally rests on the periphery of the disk 59 at the insulated point 62 thereof. Engaging the pinion 69 is a small gear wheel 74 which is fixed to a short 'shaft .extending through the plate 49 and ,supporting on the other side of the plate a ratchet wheel 75. This ratchet wheel is provided with a retaining pawl 76 and a drivingpawl 77, the latter pivoted to the armature 7 8 of the magnet 24. The armature 78 is pivoted to an extension piece 79 of a bar 81, which is a part of the frame, and extends between the plates 49 and 35. This bar 81 supports the magnets 25. A similar bar 82, also a part of the frame and extending between plates 49 and 35, supports the magnets 26.

Each pair of magnets 25, 26 with their armatures 83 and 84, respectively, together with the stepping and retaining pawls 85 and 86 comprise a mechanism for stepping and releasing the ratchet wheel 87. There ist are seven such ratchet wheels, one for each section of the recorder. Each ratchet and a Contact carrying arm 89 are formed integrally with a hub 88. This arm carries a pair of contact-springs 91, 92, the latter resting normally against an angular extension 93 of the arm. The contact spring 91 is connected to aspiral conducting and retracting spring 94, the outer end of which is fixed to; an insulating pin 95 of the arm 89, and the inner end of which is secured to but insulated from the stem 34.

Each of the seven electromagnets 22 has an armature 96. A lever 97 to which the armature is secured is pivoted at 98 in a slot in the circular plate 33 and rests at its free end in one of seven. peripheral slots in a circular plate 99 secured to the stem This lever extends beyond the plate 99 in position to be engaged by the pin 60v of the disk 59.

The disk 59 has a tendency, by tension of the spring 66, to turn on the shaft 57, but is prevented from turning by engagement of the pin 60 with the end of the lever 97 of one ofthe seven electromagnets 22. lWhen the armature 96, however, is attracted the disk rotates until the pin strikes the next leverl 97 that is in normal position. This will carry the Contact ring on the disk 59 to a point where the brushl 73 no longer rests on the insulating point 62 anda circuit which will be described hereinafter in connection with Fig. 1) is closed to oiperate intermittently the electromagnet 24. This magnet thereupon .oscillates its armature, causing its pawl 77 to drive the ratchet Wheel 75, thus turningthe gear wheel 74, and the latter by engagement with the pinion 69, driving the disk 68 to the point where the brush 7 3 again rests on the insulating point 62. In this manner the spring 66 is kept under tension so that the disk 59 is always ready to advance tol a new position upon the withdrawal of the lever 97 which at the moment is preventing its further movement. When the disk 59 is allowed to advance in ythe manner stated, it turnsthe pinion 56, which drives the gear wheel 55, the latter causing all of the pinions 48 to turn an equal angular distance. That is to say, when the pin 64 of the disk 59 moves, from a lever 97 to the next,- thereby moving one-seventh of a complete revolution, the pinions 48 likewise turn one-seventh of a revolution and the pins 54' onA the rods 47, which have been in position to engage their levers 38, are

`moved out of the way of engagement with those levers, while the next set of pins, corresponding to the next section of the recorder, are moved into a corresponding positiom whereby they may upon endwisermov'ement of the rods, engage the levers in that next section.

The sequence of operation of the parts of the recorder mechanism when used in connection with the code impulse signaling system herein described, will be stated more in detail in connection with the following description of the system of circuits shown in Fig. 1:

Referring to Fig. 1, which shows a system of circuits for signaling in accordance with the invention, av subscribers station 111, which comprises the usual telephone and signal receiving apparatus and hook switch 112` is connected by line wires ,113 and 114 to a central office where it may be extended through switching apparatus 115, 116 to impulse receiving and control relays 117, 118 and 119.E The switching apparatus 115, 116 may be of any form used for distributing calling subscribers lines to the call receiving apparatus. Located beside the subscribers telephone set 111 and lin the line wire 114 is a calling device 121 by which the code impulse combinations .by partial and full interruptions of the line circuit may be transmitted. The calling device is shown diagrammatically as it is not in itself the invention herein claimed. The principal elements, however, of this device are shown in their proper relation i'or adjustment and operation to transmit the desired impulses. These elements are: twol contact plates 122 and 123; three brushes 124, 125 and 126 normally resting on the plate 122; a resistance coil 127, and an adjustable commutator 128 capable of being placed in any one of twelve positions relative to the plates 122, 123 other than the normal positiornN, as shown in the diagram. These twelve positions are indicated by the numbers 0 to 9 inclusive and the letters X and Y, corresponding to the numbers and letters assigned to the twelve electromagnets 21 of the recorder. The adjustable commutator 128 may be of conduct-r ing material with insulating segments vari ously positioned therein as shown.

Preliminary to the operation of the calling device, the subscriber lifts his receiver to call, closing the line circuit at the hook .switch 112, and causing current to How from the grounded battery 129, through relays 118 and 117, switch contact 115, wire 113, hook switch 112, the telephone apparatus at substation 111', brush 125, contact plate 122, brush 124, wire'114, switch contact 116 and relay 119 to ground". The subscriber manipulates the calling device so as to cause movements as follows: First, the commutator 128 and the plates 122 and 123 move in unison downwardly until the three brushes 124, 125 and 126 rest upon the plate 123.it Second, the commutator 128 moves laterally, to the right, to a new position corresponding to the number or letter to be transmitted; assuming that this is the number 3, the new position is such that the portion of the commutator along the line 3 occupies the position designated N in the diagram. Third, the commutator `128 and plates 122 and 123 move in unison upwardly a distance equal to their previous movement downwardly, thus causing the three brushes 124, 125 and `126 in effect to traverse the face of the commutator (under thepresent assump- -`Jfion) along the line 3 and the two adjacent Vlines on either side thereof, respectively.

current will flow by way of the resistance l127, brush 126, contact plate 122 and brush *124 instead of more directly by way of brush I *flowing this partial interruption the full in- 125, contact plate 122 and brush 124. Foll terruption takes place because both brushes 125 and 126 are insulated and the circuit is for the moment wholly interrupted. Fourth, the commutator 128 returns by a lateral movement to the left to its normal position.

If the commutator were adjusted to position 9 the brushes 124 and 126 on the up-h ward movement of the commutator would lfirst pass over insulating segments andfa full interruption would -occur due to the opening of the circuit at brush 124. On approaching the middle portion of the commutator the brushes 125 and 126 would pass over insulating segments causing a second full interruption. On leaving the commutator the brush 126 would pass over an insulating segment, but no interruption would follow because the line circuit would remain closed at this time throughvbrushes 124 and 125. Thus in sending the signal 9 two full interruptions of the current occur. 1n a Similar manner other combinations of impulses may be transmitted by variously adjusting the commutator prior to moving it transversely under the brushes 124, 125 and 126. The various combinations are indicated yin Fig. 7 by graphical representations of current waves. It will thus be -readily seen that the signals 0 to 9 and X by two partial. 9, two full. X, three full. Y, two full followed by one partial.

Reference has been made to the receiving and control relays 117, 118 and 119. All of these respond by pulling up their armatures when the subscriber initiates a call by lifting his receiver from its switchhook. Relay 117 is adjusted to release its armature upon each partial or full interruption of current. Relay 118, however, is adjusted to release its armature upon each full interruption but not upon a partial interruption, while relay 119 is made slow-acting so as to release its armature only upon a continued opening of the line as when the subscriber hangs up his receiver but not during the transmission of impulses by either partial or full interruptions of current.

Associated with the recorder are four selective relays 131, 132, 133 and 134 adapted by the circuit arrangement, presently to be described, to be energized in various combinations of one or more according to the signals transmitted, and thereby to selectively control the local circuits of the recording magnets 21. There are also provided four switching relays 135, 136, 137 and 138 which cooperate with the receiving and control relays 117, 118 and 119, and with a sequence -switch 139 in the selection of the relays 131,

132, 133 and 134.

The sequence switch 139 is of a wellknown construction; it is shown diagrammatically with its contact sets located about the circuit diagram for convenience and with the various positions at which the contacts are closed indicated by the adjacent numbers. The master contact 141 determines the positions at which the seduence switch may stop temporarily. These positions, as noted in the diagram, are 1 (normal), 2, 6, 10, 14, 18, 22 and 26. The master contact is closed during the movements from each of these-stopping positions to the neXt so that when in any such positiom the circuit of the sequence switch magnet 142 is closed by some apparatus the switch will, on leaving that position, be carried to the next stopping position. In this manner the sequence switch would be carried from position 1 to 2, from 2 to 6. and finally from 26 back to 1. The sequence switch has twentynine positions.

. A continuously operating interrupter 143 is provided in the circuit of the electromagnet 24 so that when the circuit of this magnet is closed between the brush 73fand the contact ring 61 of the spring motor 23, the magnet 24 will be intermittently operated to wind up the spring motor and advance the brush 73 to its normal position at the insulating point 62 on the -disk 59. This circuit maybe traced as follows t-grounded battery 144, interrupter 143, magnet 24, brush of convenience in the diagram. Severall sources of currentor batteries are indicated,

but it will be understood that in practicethere may be and preferably would be a single battery supplying all the circuits.

The recorder herein described and as here` tofore stated comprises seven sections. It is therefore capable of recording any combination of seven numerals or letters,.and would` be applicable to a large multi-office telephone system which might be designed,

folr example, to provide for several hundredy central offices of 10,000 lines capacity each. In order to indicate the complete number, or oflice and number, of a wanted subscriber in such a system seven successive signals would betransmitted, eachl designating a numeral or letter-as for example, the number 37X 5485. Thisnumber would. be understood to mean that the subscriber wanted was in office 37X and his number in that office, 5485. To transmit this number the calling device 121 would be adjusted and operated seven successive times,.which, in the manner to be presently explained, would result 1n the several numerals and letter being set up in the seven sections respectively of the recorder. The numeral 3 in the first section, 7 in the second, X in the third, 5 in the fourth, 4 in the fifth, 8 in the sixth, and 5 in the seventh. The operation in detail is asfollowsz-The subscriber at station 111 lifts his receiver, closing at hook switch 112 the linev circuit previously traced and including the relays 117,118, and 119 which are thereupon energized. Relay 117 closes at its front contact 145 a circuit for advancing the sequence switch from position 1 to position 2, this circuit being traced from grounded battery 146 through sequence switch magnet 142, sequence switch contact 147 V(closed only in the normal position 1) and contact 145 to ground. Upon coming to rest in the second position the sequence switch closes contacts 148, 149 and 151, thus preparing certain local circuits for subsequent operation. Contact 149 at this time completes a circuit from battery 152 through said contact 149 and the four holding coils 153 of relays 131, 132, 133 and 134 to ground. The magnetizing effect ofthe current now flowing in these holding 4c'oilsis insuflicient to actuate the ar matures of those relays, but is suflicient to retain thel armatures in attracted position after anyjof these relays is given an initial cnergization by current in its operating coil 154. Upon adjustment of the calling device in the manner heretofore stated to the third position, one partial impulse is transmitted followed by one full impulse. The first or partial impulse releases momentarily the armature of relay 117, but not that of relay 118, thus closing momentarily a circuit for the switching relay 135 as follows from grounded battery 152, through contact 149, relay 135, contact 155 of relay 136, and contact 156 of relay 117, to ground. Relay 135 draws up its armature closing contact 157, but this does not at the instant of closing cause the energization of the second switching relay 136 because the path to ground through the latter by way of contact .157 is short-circuited by the path by way of contacts 155 and 156. At the end of the par-A tial impulse, however, the relay 117 draws up its armature, and the short circuit is broken at Contact 156. Then relay 136 becomes Ienergized and relays 135 and 136 are retained energized in the locking circuit which may be traced from grounded battery 152, through contact 149, relays 135 and 136, and contact 157 to ground. The momentary release of the armature of relay 117, due to this partial impulse, had just before relay 136 was energized, closed a local circuit for the operating coil 154 and therefore had energized relay 131. This circuit may be traced from grounded battery 152, through contact 149, coil 154, contact 158 of relay 136,

contact 159 of relay 118 and contact 156 of relay 4117 to ground. The momentary flow of current in the operating winding 154 thus caused this relay 131 to open its Contact 161 and to close its contact 162, the current which continues to flow through the retaining coil 153 holding the armature in its attracted position. After this partial impulse a full impulse follows which permits the armatures of both relays 117 and 118 to momentarily close their backfcontacts 156 and' loo of the full impulse period, .the fourth.

switching relay 138 becomes energized, in a ifla ner similar to that when the second switching relay 136 had, been energized, by the opening at contact 156 of a short-circuit by way 0f contacts 164, 165 and 156 about Vits winding. Relay 138 is thereupon brought intoa locking circuit with` relay 137 from grounded battery 152 to contact 149, relays 137 and 138, and contact 167 of relay 137 to ground. It is noted that the energizing of the second switching relay 136 hadcaused the closure 0f contact 168, b ut that this closure had not resulted in the completion of any circuit because of the simultaneous opening of contact 156. Likewise the energization of the fourth switching relay 138 causes the opening of contact 169 and the closing of contact 171. Although contacts 168 and 169 had been simultaneously closed, no local circuit had been completed because relay 118 had released its armature and opened contact 159. Also the closing of contact 171 did not complete any local circuit because at the vmoment of its closure contact 156 of relay 117 was opened. In transmitting the signal to indicate the numeral 3, only two impulses, the. first aA partial and the second a full impulse, are

required. Some of the signals, however, require three impulses. In all cases, at the end of the second impulse the fourth switch` ing relay 138 ,is beingenergized and closes at Contact 172 a circuit for advancing the sequence switch 139, the latter passing from the second to the sixth position. It will be recalled that the only selective relay operated on the transmission of the signal 3 was the relay 131. Therefore, the local circuit of the recording magnet 21, designated by the numeral 3, is momentarily energizedf' as the sequence switch passes the fourth position, the circuit being as follows :-from grounded battery 173, through sequence 'switch contact..171, the fourth electromagnet 21-designatcd 3-contact 175 of relay 134., contact 176 of relay 133, contact 177v of relay 132, and contact 162 of relay 131 to ground. The recorder being in normal position the stop pin is in mechanical engagement with the lever 97 of the stop magnet 22, thus maintaining the register in position to establish a record in its first section. The energization of the electron'lagnet 21 causes its armature 51 to be drawn toward the core 50, the rod 47 to be moved endwise and the pin 5l in the first section to engage the outer or yoke end of the lever 38 which occupies the position 3 corresponding to the energized electromagnet. This lever is thus rocked so as to present its longer arm 42 in line with the contact spring 92, and although the magnet 21 is but momentarily energized, the lever, by its frictional engagement with the edges of the hars 39, remains in its displaced position. Thus a record of the signal 3 is made and retained in the first section of the recorder. ln its continuous movement from the second to the sixth position, the sequence switch after passing the fourth position opens its contact 149, thus releasing and allowing the restoration of' the four switching relays 135,

136, 137 and 138, and also the selective relay 131. Also in passing the fifth position sequence switch contact 178 is closed causing a momentary energization of stop magnet 22, thus withdrawing the lever 97 from the pin 61 of the disk 59 of the spring motor 23, permitting the latter to advance the pin 61 to the lever 97 of' the next stop magnet 22. This movement causes the pinion 56 to drive the gear-wheel 55 and the latter to turn all of the twelve pinions 18 one-seventh of a revolution. These pinions being supported on the keyed portion of the rods 417 turn the latter an equal angular distance thus carrying the pins 51 of the first section out of position for theoperation of the levers 38 in that section and bringing the pins 54 of the second section into position for engagement with the levers 38 in that section. rll`he foregoing states the operation for transmitting the numeral 3.

The other numerals and letters of the subscribers number 37X y5185 are now transmitted, and in a similar manner, the only difference being that the local circuits are differently operated and different ones or combinations of the selective relays 131, 132, 133 and 134 energized.

The second numeral 7 is sent vby transmitting one full 'followed by one partial impulse. `The full impulse, which causes the momentary release of the armatures of both relays 117 and 118, merely effects thev operation of the first and second switching relays 135 and 136, in the manner previously described, but does not effect the operation of any of the selective relays for the reason that no local circuit is established at this time serially through the back contacts 156 and 163 of the relays 117 and 118, respectively, since contact 166 of the fourth switching relay is not yet closed. The second or partial impulse, however, results in the operation of the selective relay 132 for the reason that the contact 168 of the second switching relay 136 is noW closed and a circuit is established from grounded battery 152, through sequence switch contact 149 (now closed in position 6), through the operating Winding 154 of said relay 132, contact 169 of the fourth switching relay 138, (this contact is not opened until the end of the second impulse), contact 168 of relay 136, contact 159 of relay 118, and contact 156 of relay 117 to ground. In the same manner as before described, the contact 172 of the fourth switching relay 138 is closed at the end ofthe second impulse. This causes the sequence switch- 139 to advance from position 6to position 10, and. in passing position 8 to operate the eighth recording electro-magnet 21-designated 7. ls'o on entering the ninth position *the switching relays 135, 136, 137 and 138 and the selective relay 132 are released by the opening' of sequence switch contact 149. In this position also stop magnet 22b 1s energized by the vclosing of sequence switch contact 179, thus releasing the spring motor 23 and allowing the recorder to advance the rods 47 and the pins 54 thereona into a new position which prepares the recorder for registering the next numeral or letter in the third section. The numeral 7 is thus registered in the second section of the recorder. v

The next character transmitted is X, and upon the proper adjustment of the calling device there are transmitted three full impulses. VAThe first, in the same manner as previously described, merely results in the operation of the two switching relays 135 and 136, but does not operatev any of the selective relays. The second impulse results in the operation of the third and fourth switching relays 137 and 138, but as the contact 166 is not closed until the moment just following the completion of this impulse, it does not result in the operation of any of the selective relays. The third impulse, it will be noted, occurs after contact 172 of switching relay 138 is closed, and thus after the sequence switch 139 has started ,on its travel from the tenth to the fourteenth position. The operation of the calling device is sufficiently rapid," however, so that this third impulse is completed before the sequence switch reaches the twelfth position in which the recording takes place. This third impulse resulting as it does in the momentary release of the armatures of relays 117 and 118, therefore, closes a circuit for selective relay 134 as followsz-from grounded battery 152, through sequence switch contact 149 (at this moment the sequence switch `may be passing the eleventh position), operating winding 154 of relay 134, contact 166 of relay 138, contact 163 of relayI 118, and contact 156 of relay 117 to ground. On reaching the twelfth position the eleventh recording electromagnet 2l-designated ,X-is operated thusregistering that character by a displacementA of the eleventh lever 38 in the third section of the recorder. On entering the thirteenth position the switching relays and the operated selected relay 134 are released as before,

and in this position also stop magnet .22c is energized by the closing of sequence switch contact 181, releasing the spring motor and allowing it to Qldvance the recorder from its third to its fourth section.

The next character to be transmitted is the numeral 5. In this case the impulses are one partial followed by two full. The first, a partial impulse, resulting in the release of the armature of relay 117, but not of that of relay 118, causes the energization of selective relay 131, in the same Way as was caused in the case of transmitting numeral 3. The second being va full impulse and relays 131 and 134 are energized, and when the sequence switch is passing position 1,6 the sixth recording electromagnet 21des1g nated 5 -is operated, thus registering the number 5 in the fourth section of the recorder. On leaving the sixteenth position the switching and selected relays are released as before, and. i'n the seventeenth position the stop magnet 22d is energized by the closing of sequence switch contact 182 thus advancing the recorder from its fourth t its sixth section. l

The next character sent is the numeral 4 by the transmission of one partial, followed by one full, followed by one partial impulse. In this case the first impulse results in the energization of selective relayv 131 in the manneralready described. The second impulse merely operates the third and fourth switching relays 137 and 138, but does not operate any selective relay, while the third being a partial impulse results in the operation of selective relay 133 over the following circuit z-from grounded battery 152, through sequence switch contact 149 (now closed in position 18), operating vcoil 154 of relay 133. contact 171 of the fourth switching relay 138 (now energized), contact 168 of the second switching relay 136, contact 159 of relay 118, and contact 156 of relay 117 to ground. In this case the relays 131 and 133 are energized and therefore when the sequence switch passes its twentieth position the fifth recording electromagnet 21- designated 4-is operated, thus registering the numeral 4 in the fifth section of the recorder. -On leaving the twentieth position the switching and selected relays are released by the opening of sequence switch contact 149, and inthe twentieth position thestop magnet 22e is operated by the closure of sequence switch contact 183,. thus causing the recorder to advance from its fifth to its sixth section.

The next character sent is the numeral 8 transmitted by one full followed by two partial impulses. The first or full impulse as before merely operates the switching relays 135 and 136, but does not operate any selective relay. The second, a partial impulse, results in the energization of selective relay 132 in the same manner as before described, and the third, also a partial impulse, results in the energization of selective relay 133. In this case, therefore, selective relays 132 and 133 are energized, and when the sequence switch passes its twenty-fourth position, the ninth recording electromagnet 21- designated 8 -is energized thusregistering numeral 8 in the sixth sectionl of the recorder. On leaving the twenty-fourth position the switching and selective -relays are released, and in the twenty-tifth position the stop magnet 22f is energized by the closing of sequence switch contact 184 thus causing the advance of the recorder to its seventh or last section.

The last numeral of the number of the subscriber wanted is 5, which is transmitted by one partial followed by two full impulses. As before stated, thisl results in the energization of switching relays 131 and 134. 0n passing its twentieth position the sequencel switch closes circuit for the sixth recording electromagnet 21-designated 5 -thus registering the numeral 5 in the seventh or last section of the recorder. On leaving the twenty-eighth position the switching and selected relays are released, and in the twenty-ninth position the last stop magnet 22g isenergized by the closing of sequence switch contact 185, thus permitting the spring motor 23 to advance the recorder from the seventh section to the iirst or normal position again.

There are now registered in the vseven sections of the recorder by the displacement of certain of the levers 38, the wanted subscriber-s number 37X 5485.y The numerals or letters just registered may be read or made manifest in any desired manner. The means shown by which an arm 89 in each section carrying contacts 91 and 92 may be stepped around from normal position to count the records, is preferred, as it is suitable for the control of selector switches in an automatic telephone exchange. The stepping and release magnets 25 and 26, respectively, may be operated by any desired circuit arrangement in4 association with such selectors, and it will be apparent that upon energization of the magnet 26 and the intermittent operation of the magnet 25, the arm 89 will be stepped around toward the displaced lever 38 in that section. Y The number of steps taken to bring the spring 92 into engagement with the twisted end of the arm 42 of the lever 38 determines the position of that lever. four steps to advance the arm in the first section to the displaced lever 38- therein; in the second section, eight steps; in the third, eleven; in the fourth, six; in the fifth, iive; in the sixth, nineyand in the seventh, siX.

`These operations may take place simultaneously or successively, according to the requirements of the system. 'lhe shape of the arm 42 of the lever 38 is such that at the moment the arm 89 has advanced vso as to be in line with the lever, the spring 92 will be iiexed to make contact with the spring 91, and this contact may be utilized to indicate the number of steps taken up to that time. Preferably the arm 89 would be ad- Thus it would require i vanced in every case thirteen steps, the last step bringing the arm into engagement with the spring 186 and causingA a momentary opening of the contact between that spring and the spring 187. The opening of this contact may cause the de'e'nergization of the electromagnets 25 and 26 to allow the arm 89 to be retracted to normal position. In its return movement the spring 92 carried by the arm engages the displaced lever 38 again but on the reverse side of the twisted end 42, and as this spring is held lfrom movement in one direction by the angular extension 93 it will force the lever, which had been held in displaced position by friction merely, back to its normal position. In this manner any number registered on the recorder, after being counted by the stepping operation, may be erased to prepare the recorder for another operation.

Restoration of the sequence switch and apparatus controlled thereby may be had at any time during the operation of transmitting a signal by the subscriber at the substation 111 hanging up his receiver.v l`his at'any time the sequence switch is oli' normal position will result in the deenergization of relay 119, which as has been stated, is of the slow-release type so that its armature is held up continuously during the transmission of the signaling impulses. The hanging up of the receiver, however, opens the line circuit at the hook switch 112, allowing relay 119 time to 'release its armature and close its contact 188. for the sequence switch as follows from grounded battery 146, through sequence switch magnet 142, sequence switch contact 148 (closed in all off-normal positions- 2 to 29 inclusive), and contact 18S to ground. The sequence switch is thus driven continuously from any olf-normal position to normal. Each of the stop magnets will be energized successively in such case per- 'mitting the spring motor 23 to drive the recorder around to normal position.

The operation in detailhas been followed for the t 'ansmissiom translation, recording and reading of a particular signal, the number 37X 5485. It will be apparent that in a similar manner any number made up of a combination of seven or less numerals and letters may be transmitted, translated, recorded and read, and in each case the several characters-numerals or lettersof the number are separately registered in the different sections of the recorder. The registering elements of the recorder are automatically adjusted after recording each character so as to prepare it for recording the next character in the next succeeding section.

`Each character is transn'iitted by a series of impulses, the maximum number of which is three and the minimum two. The ad- ]ustment of the recorder from sectlon to This completes a circuit section takes place automatically following the second impulse in each case,v but the actual shifting of the recording parts is delayed slightly to permit a third impulse for certain of thehcharm-ters to take place prior to the shifting. llach character transmitted results in the operation and locking up of one or more of the selective relays 131, 132, 133 and 134. The first impulse, if partial, is registered by the operation of relay 131, but if full does not lock up this relay and is therefore registered, it may be said` by thenon-operation of this relay. In other words, the first impulse it partial causes contact 16'.) of' relay 131 to be closed, whereas if full it allows the contact 161 to remain closed. The second impulse in a similar manner will result, if partial, in the energization ofselective relay 13:2, but if full, in the non-operation ot' this relay. The third impulse u ill likewise be partial or full, or it may be lacking. It' partial, selective relay 133 is energized, and if full. selective relay 13-1. In case there is no third impulse, neither of' these relays is energized. There are thus three possible conditions of' the selective relays 133 and 131 following the second impulse. It will thus be seen that in the method of signaling according to this invention, there are twelve combinations or permutations-the product of' 2 2 3- Other arrangements ot' circuits and other types of apparatus may be devised which are capable of use in accordance with the method and system of this invention, and the invention is therefore not limited to the particular system of circuits and apparatus disclosed.

I claim:

1. Method of signaling which consists in closing a circuit to current, producing impulses therein by :full and partial interruptions ofcurrent arranged in combinations differing in the number of interruptions and in the order of the full and partial interruptions, registering each interruption individually and recording each combination according to al numerical system.

2. Method of signaling which consists in transmitting impulses of two different kinds produced by full and partial4 interruptions of' current and arranged in combinations differing in the number and kind of' the impulses and in the order of the impulses of different kinds, and recording each combination.

3. kMethod ot" signaling which consists in transmitting impulses ofl two different kinds produced by t'ull and partial interruptions of'current and arranged in combinations otl a maximum of three and a minimum of two impulses, and recording each combination.

l. Method of electric signaling which consists in transmitting impulses of two kinds produced by full and partial interruptions of' current and arranged in combinations of a maximum of three and a minimum of two impulses. the first and second impulses being of one kind or the other and the third impulse being of' one kind or the other or being omitted, and recording each combination.

5. In a signaling system the combination with a line circuit extended between stations, a switch for closing the line at one station, a source ofl current for the line at another station. means at the first mentioned station for producing current diminutions varying in strength arranged in combinations differing in the order ot' the impulses of tlifferent strengths, and a receiving device at the other station for recording each combination.

In witness whereof, I hereunto subscribe my name this 10th day ofA July, A. D. 1913.

JOHN G. ROBERTS. 

